Study On The Nature Of ?₀(980) And Z_c(4025) Based On The BES? Measurements

Hadron physics is one of the hot topics in particle physics and nuclear physics.It is of great significance to understand the non-perturbation properties of quantum chromodynamics and to study the properties of hadrons based on the experimental measurements.We have studied the nature of a0(980)and Zc(4025)based on the BES? measurements on the processesD+??+?0? and e+e-?(D*D*)�,0?(?),0.The nature of the low-lying light scalar mesons is still problematic and there are many explanations about their nature.The BESIII Collaboration has measured the D+??+?0? decay,but the phase-space Monte Carlo distributions do not agree well with the data distributions due to the possible intermediate resonances.Taking into account that the scalar a0(980)can be dynamically generated from the pseudoscalarpseudoscalar interaction within the chiral unitary approach,we have studied the single Cabibbo suppressed process D+??+?0?.We find clear peaks of a0(980)+and a0(980)0 in the ?+? and ?0? invariant mass distributions,respectively.The predicted Dalitz plots of D+?+?+?0? also show the significant signals for a0(980)+and a0(980)0,which provides some theoretical basis for the experimental measurement and can be used to test our model in future.Our study shows that the process D+??+?0? can be used to explore the nature of the scalar a0(980),thus we encourage the experimental physicists to measure this reaction with more precision.On the other hand,the nature of most charmonium-like states cannot be explained by the conventional cc picture.There are many explanations about Zc(4025)since the BESIII Collaboration observed this state in 2014.The Zc(4025)mass is close to the D*D*threshold,and an enhancement near the threshold could be a reflection of a bound state below threshold most often.We have analyzed the e+e-?(D*D*)�,0?(?),0 reactions at(?)GeV by involving the vector-vector meson interaction for the channels D*D*,K*K*,pp within the unitary coupled-channel approach.We have calculated the D*D*invariant mass distributions in the e+e-?(D*D*)�?(?)and e+e-?(D*D*)0?0 reactions respectively,which agree well with the experimental measurements,and the pole found in the second Riemann sheet corresponds to the D*D*bound state.we conclude that the enhancement of Zc(4025)reported by the BES? Collaboration could be the reflection of a JP=1+D*D*bound state below threshold.In summary,this work shows that the process D+??+?0? can be used to understand the nature of the scalar a0(980),and the enhancement of Zc(4025)measured in the e+e-?(D*D*)�,0?(?),0 reactions could be the reflection of a JP=1+ D*D*bound state below threshold.